Super "Weight Loss" Method for IO.SYS - China DOS Union Forum

The MS-DOS 7.10 boot disk is undoubtedly the most practical boot disk. Unfortunately, the IO.SYS is usually too large, occupying more than 200K of space on the floppy disk, which is really not worth it. A few days ago, I saw that Roy successfully split the DOS program part of REGEDIT.EXE, which gave me great inspiration. Therefore, I decided to also split the IO.SYS of MS-DOS 7.10. After some research, I found that the IO.SYS file of MS-DOS 7.10 is actually composed of three parts. One part is the code required for booting (121K), the second part is the embedded compressed boot logo image (65K), and the third part is the file image part (32K), which is basically useless. After testing, I successfully cut out the second and third parts from the IO.SYS file. At this time, it is only 121K in size (100K smaller than the original) and can boot normally, and the original Win98 logo screen is no longer there!

In this way, it has become the real IO.SYS of MS-DOS 7.10. Here it is uploaded:
Open the attachment The link is invalid (Administrator's note)

If you want to implant your own logo image, how to do it?

The moderator, you are so amazing. Can you teach me how to see how many parts it is divided into? Thank you!!

Wengier, can you please tell me the addresses (offsets) of those three parts?

Part 1: 00000H - 1E605H (Header)
Part 2: 1E606H - 2E9FFH (LOGO)
Part 3: 2EA00H - 36B95H (Image)

By the way, I tried it in VPC, but it can't boot.

But it can boot from my hard disk (C:\).

Still Wengier is powerful. This problem has only been solved by you so far.

I tried it, only can boot from the hard disk, not from the floppy disk.

Why does Roy know that? Maybe it's because of the file header. Because the file size has been changed, the preceding file header information also needs to be modified accordingly, but I can't change this part.

I tried to correct the file header, but it still doesn't work on the floppy disk.

Can you please tell me the specific method? And which tools are used?

Then I want to know, what are the differences in the code executed by IO.SYS during booting from a floppy disk and a hard disk? Why do the effects differ?

Also, Roy, take a look at the LOGO in the second part. What compression format is it? It seems the compression ratio is not high, only about half. If we can figure it out, we can put our favorite LOGO inside it.

Floor1　Wengier	Posted 2003-04-18 00:00
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The MS-DOS 7.10 boot disk is undoubtedly the most practical boot disk. Unfortunately, the IO.SYS is usually too large, occupying more than 200K of space on the floppy disk, which is really not worth it. A few days ago, I saw that Roy successfully split the DOS program part of REGEDIT.EXE, which gave me great inspiration. Therefore, I decided to also split the IO.SYS of MS-DOS 7.10. After some research, I found that the IO.SYS file of MS-DOS 7.10 is actually composed of three parts. One part is the code required for booting (121K), the second part is the embedded compressed boot logo image (65K), and the third part is the file image part (32K), which is basically useless. After testing, I successfully cut out the second and third parts from the IO.SYS file. At this time, it is only 121K in size (100K smaller than the original) and can boot normally, and the original Win98 logo screen is no longer there! In this way, it has become the real IO.SYS of MS-DOS 7.10. Here it is uploaded: Open the attachment The link is invalid (Administrator's note)

Floor2　如是大师	Posted 2003-04-18 00:00
元老会员　Posts 3,351　Credits 9,654　From 湖北
Good

Floor3　fjpc	Posted 2003-04-18 00:00
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If you want to implant your own logo image, how to do it?

Floor4　Dark-Destroy	Posted 2003-04-18 00:00
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The moderator, you are so amazing. Can you teach me how to see how many parts it is divided into? Thank you!!

Floor5　Roy	Posted 2003-04-18 00:00
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Wengier, can you please tell me the addresses (offsets) of those three parts?

Floor6　Wengier	Posted 2003-04-18 00:00
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Part 1: 00000H - 1E605H (Header) Part 2: 1E606H - 2E9FFH (LOGO) Part 3: 2EA00H - 36B95H (Image)

Floor7　Roy	Posted 2003-04-18 00:00
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By the way, I tried it in VPC, but it can't boot.

Floor8　Wengier	Posted 2003-04-18 00:00
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But it can boot from my hard disk (C:\).

Floor9　MYS	Posted 2003-04-18 00:00
元老会员　Posts 1,637　Credits 5,170　From 广东佛山
Still Wengier is powerful. This problem has only been solved by you so far.

Floor10　Roy	Posted 2003-04-18 00:00
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I tried it, only can boot from the hard disk, not from the floppy disk.

Floor11　Wengier	Posted 2003-04-18 00:00
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Why does Roy know that? Maybe it's because of the file header. Because the file size has been changed, the preceding file header information also needs to be modified accordingly, but I can't change this part.

Floor12　Roy	Posted 2003-04-18 00:00
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I tried to correct the file header, but it still doesn't work on the floppy disk.

Floor13　LanE	Posted 2003-04-18 00:00
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Can you please tell me the specific method? And which tools are used?

Floor14　Wengier	Posted 2003-04-18 00:00
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Then I want to know, what are the differences in the code executed by IO.SYS during booting from a floppy disk and a hard disk? Why do the effects differ?

Floor15　Wengier	Posted 2003-04-18 00:00
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Also, Roy, take a look at the LOGO in the second part. What compression format is it? It seems the compression ratio is not high, only about half. If we can figure it out, we can put our favorite LOGO inside it.